In vitro selection of DNA aptamers which bind to cholic acid

Electrochemical detection of 17β-estradiol using DNA aptamer immobilized gold electrode chip

“…A total of seven cycles of repetitions and enzymatic enrichment were carried out for this selection. Ten ssDNA aptamers obtained finally from SELEX process were analyzed in terms of their affinity to 17␤-estradiol based on the equilibrium-filtration method (Jenison et al, 1994;Kato et al, 2000). The dissociation constants for 10 ssDNA aptamers were in the range of 0.1-3 M. In this study, one of the 10 ssDNA aptamers showing a constant of 0.13 M was selected as a final probe DNA aptamer molecule.…”

Current research activity in biosensors

“…This methodology is called "in vitro selection". Since an aptamer consisting of DNA was designed for binding with protein in 1992 [34], various DNA aptamers have been designed to bind with thrombin [35], a transition state analog [36], bile acids, using enzyme-linked DNA aptamer [37], cholic acid [38], steroids using three-way DNA junctions [39], or rat brain tumor microvessels [40]. In addition, RNA aptamers can be adapted to biosensor applications by directly transduced molecular recognition of ATP, affording optical signals, although RNA is unstable compared with DNA as a recognition element [41].…”

Analytical potential of gold nanoparticles in functional aptamer-based biosensors

“…Aptamer binding affinity constants can be validated to confirm its specificity and affinity for the target by using techniques such as isocratic elution, equilibrium gel filtration, microdialysis, ultrafiltration, fluorescence, and surface plasmon resonance spectroscopy [29][30][31][32][33][34][35]. For example, the most commonly used aptamers for human α-thrombin were screened out by two groups using SELEX process, respectively [36,37].…”